
<html>
<style>
	html,body{
		margin: 0;
	}
	input{
		margin: 20px;
		width: 200px;
	}
</style>

	<input id="input" type="text"  placeholder="http://b.jrg.com:8080/b.html">
<script>
// URL: http://b.jrg.com:8080/b.html
 
document.querySelector('#input').addEventListener('input', function(){
	window.parent.document.querySelector('input').value = this.value;
})
document.domain = 'jrg.com';
</script>
</html>